Telephone system



J. rg. LEvls, 1R. TELEPHONE SYSTEM.

APPLICATION FILED NOV. I5. I9I5.

'Iatented Nov. 2L 11922.

l? il JOHN H. LEY/"XS, JR., OF ROCHESTER,

NEW YORK., ASSEGNE TO STROTJIBEtG-CARLSON TELEPHONE MANUFACTURNG' CUMPANY, OF ROCHESTER, NEW YORK, A COB/f90- TELEPHONE SYSTEM.

Application filed November 1.5, 1915. Serial No. 61,455.

To all fuw//n/ it 71mg/ commet.'

Be it known that l, Jenn lil. luivis, Jr., a citizen or' the United States, residing` at Rochester, in the county oit Monroe and State ot New York, have in.'cnted a certain new and use'l'ul Improvement in Telephone Systems. ot which the 'following is afully clear, concise, and exact descriptimi7 relierence being had to the accompanying drawings, iiorniing apart oit this specilication.

My invention relates to telephone systems and more particularly to the supervisory apparatus at the central station tor giving a distinct and positive recall signal when a subscriber has inished one conversation and desires to be disconnected 'from the line oit the subscriber with which his previous conversation was carried on, and to be connected to the line ot' another subscriber.

rlhe obj cet oit the present invention is to provide an improved and sinipliiied system for giving` a distinctive and positive rec ll signal.

In the accompanying drawingql in which l have illustrated diagrannnatically one lorin which n'iy invention niay take. l, have shown apparatus applied to the answering` end ot the cord circuit Yfor giving a distinctiveI recall signal. cGenerally it is the calling subscriber who is especially in need oit quick recall. service. This is due to the 'lact that a subscriber will make a number of calls in succession7 as 'for example7 where one bank calls practically every other bank in the city in quick succession in balancing up the days account. arises where a subscriber wishes to purchase a certain article and calls up all ot the dealers in this line, in succession7 ior prices. lin such situations a positive and distinct recall signal will save inuch annoy ance and delay. .ln carrying out in y invention, l employ an interrupter which is placed in series with the calling supervisory signal when the subscriber inalzes a recall.

The single ligure on the drawings is a diagrammatic representation oi' a telephone system embodying iny invention.

A plurality ot subscribers stations such as A and B, are connected by suitable line wires to the central station (l, where these lines are provided with the usual signaling and switching apparatus.

The calling station ifi is connected by the line wires 1 and 2te the switching acks 3 A similar situa-tion' and l, which are suitably multiplied together and any one ot which may serve as an answering jack it so desired. rThe jack thimbles are connected by the third wire G through the cut-oil relay 7 to ground at G1. The line wires l and 2 are connected through the armatures 9 and ll) to the battery l?) and ground G2 respectively. The line relay 1l is connected in series with the battery connection and its armature l2 controls a line signal i3 to give the calling signal. lllhen the subscriber raises the receiver troni the switch-hook to nia-ke a call, and thereby connects together the line wires l and 2 through the substation instrument, the line relay 1l is energized attracting its armature l2 and thereby displaying the lainp signal 13 to the operator to indicate a desire tor a connection. rlhe operator observing the signal, inserts the answering plug 14 in the answering jack fl to inquire et' the calling subscriber the nuinbery et the line which it is desired to call. wWhen the plug lat is inserted in the jack il, the cut-oit relay 7 is operated over the following circuit:

Ground at (il, cut-oil relay 7, jack ll', sleeve Contact ot the plug lll, third wire 15 ot the cord, through the third wire relay R1 over the battery bus 16 to grounded battery at G.

The armature 17 ot the relay .ll is thereby attracted and the answering supervisory lamp lll would be energized except that its circuit is broken at the armature 1S ot the supervisory relay R2. The supervisory relay Rg is energized over the following circuit:

Battery B, bus l5, wire 19, through one winding of the relay R2 to the tip strand 20 ot the cord, thence over the tip side ot the line l, through the substation instrument bac-lr over the line 2 to the sleeve strand 2ly of the cord circuit, wire through the other winding 'et relay R2. and to ground at The two parts ot' the winding of the relay 'l2 are wound cuinnlatively, vand as long as the switchfhook at the substation A is closed, the relay R2 will relnain energized and will hold its armatures 18 and 23 in attracted position. The operator connects her telephone set 24 to the cord by operating the key K and having ascertained the number of the desired subscriber, inserts the calling plug 25'in the jack 26 ot' the desired subscriber which in this case is the subscriber at the substation B. rIhe third wire relay R5 is energized by the insertion or' the plug 25 in jack 26 and it attractsr its armature 27 to energize the called supervisory lamp L2 as the subscriber at the substation B has not yet responded. The called subscriber is rung in the usual manner and upon response of the called subscriber, the supervisory relay R4 is energized to attract its armature 28 to extinguish the calling lamp L2. Conversation is carried on in the usual manner and upon either subscriber restoring his receiver' to the switch hook to break the corresponding line circuit, the corresponding supervisory relay is dfi-energized and the corresponding supervisory lamp is lighted toindicate that the cord circuit is to be disconnected.

Assume, however, that the calling subscriber desires another connection instead of giving the disconnect signal, he restores his receiver to the switch hook and then raises it again to give the recall signal. When the subscriber at the substation A restores his receiver to the switch hook the supervisory relay R2 is cle-energized and its armatures 18 and 23 fall back to their back contacts. The third wire relay R1 is energized since the plug 14 is in the j ack 4. Likewise, the third wire relay R5 is energized as the 'corresponding calling` plug is still in the jack. rIlhe relay R5 prepares a circuit for energizing the locking relay R3, this locking circuit being closed at the armature 23 and its back contact of the relay R2 when the same is dei-energized. This circuit may be traced as follows:

Battery B, battery bus 16, third wire 31, armature 27 of the relay R5, wire 32', armature 23 of the relay R2, wire 33, winding of the relay R3, and ground at G5.

The relay R3 is energized and it attracts its armatures 34 and 35, the armature 34 closing a locking-circuit for` the relay R3 by way of the wire 36, key contact 30, wire 29, armature 17 of the relay R1, wire 15, battery bus 16 and battery at B. 'Ihe relay R3 is now locked up and held energized so that when the subscriber at substation A again raises the receiver to give the recall signal, the circuit oi the relay R3 will. not be broken, although its first energizing circuit through the armature 23, is broken, by energization of the relay R2. The armature 18 of the relay' R2 is attracted to its liront contact and closes an energizing circuit for the lamp L1 over the following circuit:

Ground at G4, lamp L1, armature 18, wire 37, armature 35 of the locking relay R3, wire 38, winding of the pilot relay 39, in- 'terrupter I, to battery B.

The interrupter I, interrupts the flow of .current in a characteristic manner to flash the lamp L1 thereby indicating that the calling subscriber desires further connection. A suitable pilot light L3 common to a number of cords, has its circuit controlled by the armature 40 of the relay 39. It can thus be seen that the lamp signal L1 will be displayed in a characteristicmanner to give a recall signal. rIhe operator will then operate the key K to ascertain the wants of the subscriber A, and in operating the key K, opens the locking 'circuit oi the relay R3 thereby obliterating the recall signal. Alfter the completion of a seco-nd connection, the subscriber A may give a disconnect signal or may give another recall signal as desired. Giving of the recall signal is dependent upon the act of the calling subscriber and upon energization of the third wire relay in the calling end of the cord.

It is to be understood that the recall signal may be installed upon the calling end of the cord or upon both ends, if desired.

While I have described my invention with reference to a particular embodiment, I desire that the appended claims be construed as not limited to the precise details of construction shown, but to include suchmodications and variations as will be apparent to those skilled in the art, and all such minor changes and deviations as will be made to fit particular installations, I consider to come within the spirit and scope of my invention.

What I claim is:

1. In combination, a supervisory lamp, a sleeve relay, a supervisory relay, a locking relay, a source of steady current and a source ot distinctive signaling current for illuminating said supervisory lamp, the circuit oi said lamp being controlled directly by said sleeve relay and said supervisory relay to connect it to said source of steady current, and being controlled directly supervisory relay and said locking relay to connect it to said source of distinctive signaling current to give a distinctive recall signal, the connection of said supervisory signal to said source of distinctive signaling current being cut through the contacts of said locking relay.

2. In combination, a cord circuit, a supervisory lamp, an answering' sleeve relay, a calling sleeve relay, a supervisory relay, a locking relay, said locking relay having a circuit controlled by said calling` sleeve relay and said supervisory relay, and an interrupter, said lamp being switched from the control of said answering sleeve relay to the interrupter circuit,` said interruptor circuit being under the control oi said locking relay.

3. In combination, a plurality of lines, a cord circuit for interconnecting said lines, a supervisory lamp, a sleeve relay,'a circuit controlled by said relay for causing steady illumination of said lamp, a supervisory relay, a locking relay having its initial enerby said gization controlled by said sleeve relay and said supervisory relay, and an interrupter switch, said lamp being disconnected by said supervisory relay from said first circuit and connected to said interrupter to give a distinctive recall signal.

4:. In combination, a plurality of lines, a cord circuit for interconnecting said lines, a supervisory lainp lior said cord circuit, a supervisory relay, an answering sleeve relay, a calling sleeve relay, a locking relay, an energizing circuit for said locking` relay controlled by said calling sleeve relay, a locking circuit for said locking relay controlled by said answering sleeve relay, a circuit controlled by said answering sleeve relay and said supervisory relay for causing steady illumination ofi said lamp, an interrupting switch, and a circuit for said switch controlled by said locking relay and said supervisory relay Vlor causing said lanip to give a distinctive recall signal.

5. In combination, a link circuit comprising a supervisory signal, a sleeve relay, a supervisory relay, a locking relay, a source of steady current, a source of distinctive signaling current, said sleeve relay being energized upon connection of the link circuit to a line and preparing a locking circuit ttor the locking relay and preparing a circuit from the source of steady current for said supervisory signal, and a second Sleeve relay for the other end of the link circuit energized when said end is connected to another line and preparing a circuit for initial energization of the locking relay through a back contact of the supervisory relay, said locking relay being initially energized upon deenergization of the supervisory relay, said the connectiorrrof locking relay controlling signaling current said source of distinctive to said supervisory signal.

6. In combination, a plurality of lines, a cord circuit for interconnecting said lines, a supervisory lamp, a supervisory relay having-an armature and front and back contacts, a sleeve relay, a locking'relay, said lamp being connected to the arma-ture of said supervisory relay, an energizing circuit tor the lamp connected to a back Contact ot the supervisory relay and out through the contact of the sleeve relay, said locking relay having an initial energizing circuit controlled by another back contact of the supervisory relay, and a distinctive signal operating circuit controlled by the locking relay, 'for operating said supervisory lamp.

7. In combination, a plurality oil. lines, a cord circuit for interconnecting said lines, a supervisory lamp, a supervisory relay having an armature and front and back contacts, a sleeve relay, a locking relay, said lamp being connected to the armature of said supervisory relay, an energizing circuit for the lamp connected to a back contact of the supervisory relay and cut through the contact of the sleeve relay, said locking relay having an initial energizing circuit controlled by another back contact of the supervisory relay, and a distinctive signal operating circuit controlled by the locking relay, and a calling sleeve relay, said initial energizing circuit being cut through the contact or the calling sleeve relay.

ln Witness whereof, I hereunto subscribe my narne this 9th day of Nov. A. D. 1915.

JOHN H. LEVIS, JR. 

